Mechanisms for opening and closing the baking mould units in generic baking devices are known, for example, from DE 94 17 702 U and DE 196 17 804 Cl. In these known solutions, an upper mould half of each baking mould unit runs, upon entry into the operating region, onto a fixedly arranged control track arrangement extending in the circumferential direction, which extends in curved fashion according to the desired opening and closing profile.

Upwardly inclined sections of the control track arrangement result in a lifting of the upper mould halves from the lower [mould halves, whilst the] downwardly inclined sections results in a lowering [of said upper mould halves]. According to this principle of operation, the drive which is used for the rotation of the baking mould

units must additionally supply the force which is required in order to drive the upper mould halves up the upwardly inclined control track sections against the force of gravity. In the case of the often bulky and heavy design of the baking mould units, this can mean considerable additional loading of the rotary drive, particularly taking into account that the mould halves need to be sufficiently separated in order to provide adequate space for the removal of the fully baked moulded elements and the introduction of fresh moulding substance into the baking mould units. It is necessary to dimension the rotary drive so that it has a correspondingly high capacity, which can lead to a disproportionate cost increase in an electromotor drive, for example.

It is therefore the object of the invention to provide a baking device of the generic type whose rotary drive can be designed with smaller dimensions.

To this end, it is provided according to the invention that the opening and closing means comprises a lifting arrangement, which can be actuated separately to the rotary drive, for the relative adjustment of the mould halves of the baking mould units.

In the solution according to the invention, the rotary drive is relieved of lifting tasks, which in comparison with the known solutions allows for a design of the rotary drive with reduced capacity. Instead, the opening and closing of the baking mould units is undertaken by the lifting arrangement. The rotary drive and lifting arrangement can therefore be individually adapted to their respective capacity requirements.

If comparatively deep, high-walled moulded elements are to be manufactured, it is necessary to ensure following baking that the mould halves are separated in an approximately

linear manner in order to prevent collision and possible damage to the baked moulded elements contained therein. To this end, the lifting arrangement is preferably constructed as a linear lifting arrangement, which allows for a linear adjustment of the two mould halves of each baking mould unit relative to one another, whilst maintaining their reciprocal spatial orientation.

A perfectly linear separation of the axially superimposed mould halves can be attained in that one of the mould halves of each baking mould unit is fitted to the baking mould support so that it is axially non-displaceable and the baking mould support supports a guide column arrangement, on which the respective other mould half is guided in an axially displaceable but non-rotatable manner.

In view of the often very heavy construction of the mould halves, for example those made of cast metal, and the associated necessary high lifting forces, it is recommended to construct the lifting arrangement at least in part as a hydraulic lifting arrangement. However, this does not, in principle, rule out falling back on different lifting arrangements, for example electromotor or electromagnetic lifting arrangements.

In the operating station, the lifting arrangement which is disposed in stationary fashion in said operating station must grasp the incoming baking mould units in order to then execute the desired lifting procedures. The baking mould units then need to be released again from the lifting arrangement, so that they can continue their journey to the baking region. This engagement and disengagement of the baking mould units with/from the lifting arrangement can be effected in a simple and operationally reliable manner in that the lifting arrangement and each baking mould unit comprise cooperating coupling members, by means of which the lifting arrangement and the respective baking mould

unit can be brought into releasable lifting engagement, and the coupling member of one of the components: lifting arrangement and baking mould unit forms a continuous guide in the circumferential direction for the coupling member of the respective. other component. It is then possible to produce and release the lifting engagement of the baking mould units with the lifting arrangement solely by moving the baking mould units in the circumferential direction.

Although it is conceivable in principle to use a common lifting aggregate both for opening and closing the baking mould units, separate lifting aggregates are expediently provided for opening and closing the baking mould units.

This allows for a higher handling rate in the operating region and therefore increased production output, since ..... at two or more baking mould units at the same time in the operating [region]. More particularly, the lifting aggregates for opening and closing can be constructed differently. Namely, for the closure of the baking mould units and especially in, the end phase of the closing procedure, substantially greater forces are often required than during opening. This is associated with the fact that there is often a very high inner pressure in the baking mould units caused by heat and steam after leaving the baking region, which virtually drives the mould halves apart when the baking mould units are opened. In contrast, it is necessary to work against the freshly introduced moulding substance during the closure of the baking mould units in order to distribute said substance uniformly. In addition, the baking mould units usually need to be closed in a very sealing-tight manner, which contributes to the high closing forces which need to be applied.

If the opening lifting aggregate and the closing lifting aggregate are arranged spaced apart in the circumferential direction, it is expedient if the baking mould units can be held in their open position by a holding arrangement on

their journey between the two lifting aggregates. To this end, it is conceivable, for example, to provide releasable locking means on the baking mould units, which reciprocally lock the mould halves in their open position. However, it is preferably provided that the holding arrangement comprises at least one stationary holding track extending in the circumferential direction, with which a holding member constructed on each of the baking mould units can be displaceably brought into holding engagement in the circumferential direction.

The invention will be explained in further detail in the following with the aid of the attached drawings, in which: Fig. 1 is a schematic view of a production line for baked moulded elements and Figs. 2 to 5 are different partial views of a baking machine used in the production line of Fig. 1.

Recognisable in the production line shown in Fig. 1 is a conveyor 10, which transports moulded elements 14 baked in a baking station 12 and supplies said moulded elements 14 to subsequent processing stations. The moulded elements 14 can be, for example, cup-shaped or box-shaped packaging elements, more particularly manufactured from biologically degradable material, which are used for packaging foodstuffs.

The baking station 12 comprise at least one baking machine 16, in which a plurality of baking moulds, not shown in further detail in Fig. 1, rotate in succession along a closed circumferential path and in so doing pass through a baking region, in which the baking process takes place, and an operating region, in which the baking moulds are filled with fresh moulding substance and the fully baked moulded elements 14 are removed and placed onto the conveyor 10.

The filling with moulding substance or/and the removal of the moulding elements 14 can be effected manually. In order to relieve the operators of the often strenuous tasks at the baking station 12, these tasks can also be carried out automatically. To this end, a supply machine 18 for the moulding substance and a removing machine 20 for the finished moulded elements 14 can be associated with the baking machine 16.

The processing stations, to which the moulded elements 14 laid on the conveyor 10 are supplied, can comprise a separating station 22, for example, where the moulded elements 14-in so far as these are manufactured joined together in groups-are separated by cutting or punching.

Furthermore, the stations can comprise a coating station 24, where the moulded elements 14 are coated with a coating suitable for foodstuffs, for example. Before the moulded elements 14 reach a packaging station 26, where they are packaged ready for dispatch, the moulded elements 14 can pass through further stations, for example a conditioning station 28.

It has been found in practice that the capacity of the processing stations 22,24,26,28 often exceeds the rate of production of the baking machine 16. In order to optimally utilise the processing stations 22,24,26,28 and to increase the overall output of the production line, the latter, particularly in the case of a fully automated design, can comprise a plurality of baking machines 16, whose baked moulded elements 14-expediently synchronised with one another-are delivered together to the conveyor 10. If desired, the baking machines 16 can be individually switched on and off according to requirement. The idea of the production output of a plurality of baking machines 16 being taken up by a common line of successive processing stations is per se independent of the actual design of the

baking machines 16, so that the right to claim independent protection for this idea is reserved.

The design of the baking machine 16 will now be explained with the aid of Figs. 2 to 5. In this respect, Figure 2 corresponds to a plan view of a lower region of the baking machine 16, as indicated in Fig. 4 by line II-II and the associated viewing arrow. Fig. 3 corresponds to a plan view of the upper region of the baking machine 16, as indicated in Fig. 4 by the viewing direction arrow III.

Fig. 4 corresponds to a section taken along line IV-IV of Fig. 3. Finally, Fig. 5 corresponds to a view in the viewing direction of the arrow V of Fig. 3.

The baking machine 16 comprises a framework 30 manufactured from a plurality of individual struts and more particularly constructed as a welded structure, which is erected in a stationary manner. This framework 30 cannot be recognised in its entirety in Figs. 2 to 5. However, parts belonging to the framework 30 can be recognised by the corresponding reference numerals. A turntable, which is generally indicated by the reference 32 and acts as a baking mould support, is mounted on the framework 30 by means of a bearing arrangement 34 so as to rotate about a vertical axis of rotation 36. An electromotor 38, whose output shaft 40 engages with the turntable 32, is used for the rotary drive of the turntable 32. The turntable 32 comprises a plurality of table arms 42, for example eight or twelve, which are uniformly distributed in the circumferential direction, extend radially and are each connected via an adapter connection 44 with a transverse locking pin to a central table region 46 supported by means of the bearing arrangement 34 on the framework 30. The table arms 42 are supported in their radially outer region via a support bearing 50 so as to be displaceable in the circumferential direction on a circularly closed support guide track 48 extending in the circumferential direction.

The support bearing 50 can be constructed as a slide or roller bearing. The support guide track 48 is arranged in a stationary manner on the framework 30. The adapter connection 44 also optionally allows for compensating movements of the table arms 42 relative to the central table region 46, which may be necessary as a result of irregularities in the turntable 32 and/or support guide track 48 resulting from manufacture, wear or heat.

Each table arm 42 supports, preferably in a replaceable manner, a baking mould unit 52 with an upper mould 54 and a lower mould 56. The upper mould 54 and the lower mould 56 lie axially above one another. Whilst the lower mould 56 is held on the respective table arm 42 in an axially fixed manner, the upper mould 54 is guided by means of two vertical guide columns 58 fitted to the respective table arm 42 so that it is axially displaceable relative to the lower mould 56. The guide columns 58, which are arranged spaced apart, hold the upper mould 54 in its spatial orientation relative to the lower mould 56 and act as a driving element, which couples the upper mould 54 to the lower mould 56 in a non-rotatable manner.

A hydraulic lifting arrangement held on the framework 30 and generally indicated by the reference 60 is used for lifting and lowering the upper mould 54. In the open state of the baking mould unit 52, i. e. when the upper and lower moulds 54,56 are separated from one another, the moulding substance which is to be baked is introduced into the lower mould 56. Subsequently, the upper mould 54 is lowered onto the lower mould 56 and is locked to the lower mould 56 by means of a locking member not illustrated in further detail. The baking mould unit 52 closed in this manner is then moved by rotating the turntable 32 through a baking region, in which the baking mould unit 52 is heated, so that the moulding substance located therein is baked. The heating of the baking mould unit 52 can be effected, for

example, by stationary gas heating elements, or by an electric heating mechanism integrated into the baking mould unit 52. After leaving the baking region, the locking members are firstly released in a manner not illustrated in further detail. The upper mould 54 is then lifted from the lower mould 56 by means of the lifting arrangement 60, whereupon the fully baked moulded elements are removed from the lower mould 56. The latter is then ready again for filling with moulding substance. Details of a conceivable locking and unlocking mechanism can be taken from DE 94 17 702 U, for example.

The turntable 32 and therefore the baking mould units 52 are moved in clocked fashion in the circumferential direction. The opening, closing, filling and emptying of the baking mould units 52 is effected in each case during the standstill phases of the turntable 32. In order to attain a high yield, the opening and closing of the baking mould unit 52 are carried out at different circumferential locations at different clock pulse times. Thus, one baking mould unit (or even more than one) can be filled with moulding substance at the same time as a moulding element removal is effected at at least one other baking mould unit. Accordingly, the lifting arrangement 60 comprises two lifting aggregates 62,64 formed by hydraulic piston- cylinder devices, one of which is responsible for opening the baking mould units 52 and the other for closing the baking mould units 52. The two lifting aggregates 62,64 are arranged spaced apart from one another in the circumferential direction, and namely in such a manner that a baking mould unit 52 is located at one clock pulse in the operating region of the lifting aggregate 62 designed for the opening and at a later clock pulse in the operating region of the closing lifting aggregate 64. In the illustrated embodiment, the distance between the two lifting aggregates 62,64 corresponds to three clock pulses, so that one baking mould unit 52 can be opened, one

filled, one emptied and one closed at the same time, as can be seen in Fig. 5. It goes without saying that a different pulse spacing can be selected between the opening and closing of the baking mould units 52. More particularly, it is conceivable to arrange the lifting aggregates 62,64 at a distance from one another which corresponds to a single clock pulse, so that one baking mould unit 52 can be opened and emptied and another can be filled and closed at the same time.

Fitted to the upper mould 54 of each baking mould unit 52 are two elongated coupling strips 66, which extend curved in the shape of an arc in the circumferential direction and by means of which the respective baking mould unit 52 can be coupled with the lifting aggregates 62,64. At the emerging free end of its respective piston rod 68, each of the lifting aggregates 62,64 comprises a gripper 70, which is formed as a profile element curved in the shape of an arc in the circumferential direction with an approximately C-shaped cross section. With the free end of its C-cross section, the gripper 70 can engage behind the coupling strips 66 and thus couple the upper mould 54 axially to the respective lifting aggregate 62,64. In the circumferential direction, the coupling strips 66 can be pushed through the gripper 70. The coupling of a baking mould unit 52 to one of the lifting aggregates 62,64 is accordingly effected in that the gripper 70 of the respective lifting aggregate 62,64 is firstly displaced axially to the height of the coupling strips 66 of the upper mould 54 of the baking mould unit 52 which is to be coupled, whilst the baking mould unit 52 is still one clock pulse away from the lifting aggregate 62,64. By rotating the turntable 32, the upper form 54 is then moved with its coupling strips 66 into the gripper 70. After carrying out the desired lifting procedure, the coupling strips 66 are driven out of the gripper 70 by merely rotating the

turntable 32 further, which effects the uncoupling of the baking mould unit 52 from the lifting aggregate 62,64.

In order to obtain sufficient space for introducing the moulding substance and in particular for the removal of the moulded elements, the lifting height of the lifting aggregates 62,64 should measure several tens of centimetres, for example approximately 50 cm. In order to improve the linearity of the lifting movement with lifting heights of this size, a pair of vertical guide rods 72 is preferably fitted to the gripper 70 of each lifting aggregate 62,64, which are vertically displaceably guided in guide bores 74 of the framework 30. In the case of a design of the lifting aggregate 62,64 having a non- rotational piston rod 68, it even is possible under certain circumstances to dispense with the guide columns 58.

However, it goes without saying that some type of driving connection must still exist between the upper and lower moulds 54,56 of each baking mould unit 52.

So that the raised upper mould 54 does not accidentally fall back onto the lower mould 56 following the disengagement of a baking mould unit 52 from the opening lifting aggregate 62 before the baking mould unit 52 reaches the closing lifting aggregate 64, a holding profile arrangement 76, which extends curved in the shape of an arc in the circumferential direction and has an approximately C-shaped cross section similar to the grippers 70, is fixedly fitted to the framework 30 between the two lifting aggregates 62,64. The coupling strips 66 of the baking mould unit 52 run into this holding profile arrangement 76 when they emerge from the gripper 70 of the opening lifting aggregate 62. The holding profile arrangement 76 acts as a slide guide for the coupling strips 66 until the closing lifting aggregate 64 is reached. As a result of the engagement of the coupling strips 66 in the holding profile arrangement 76, the upper mould 54 is held in its raised

position. In the region of the closing lifting aggregate 64, the coupling strips 66 emerge from the holding profile arrangement 76 again and run into the gripper 70 of the closing lifting aggregate 64, which has previously been brought to the same axial height and by means of which the upper mould 54 is lowered onto the lower mould 56 again.

Particularly in the end phase of the closing procedure of the baking mould units 52, very high closing forces can be required. Consequently, it is conceivable to construct the closing lifting aggregate 64 from two piston-cylinder devices, one of which is constructed as a less powerful long-stroke device and executes a first part of the closing stroke and the other being constructed as a more powerful short-stroke device which undertakes the final part of the closing stroke.

Alternatively, the long-stroke device can undertake the entire closing and pressing procedure. The short-stroke cylinder is then used for the activation of a mechanical reciprocal locking of the baking mould halves, since the very high pressures generated during the baking procedure are only absorbed by a mechanical locking and in no way by a pneumatic or hydraulic device.

Instead of the short-stroke cylinder, it is also possible to provide a fully mechanical locking. This can be effected by a rotary cam device or an arrangement with rotatable hammer heads.

It is recommended to provide a suitable clamping device, which becomes operative in the event of sudden failure of the opening lifting aggregate 62 and prevents uncontrolled falling of an upper mould 54 which has just been raised.

This clamping device comprises clamping jaws, which in the event of failure of the pneumatic supply of the opening lifting aggregate 62 automatically reliably block the

piston rod of the opening lifting aggregate 62. However, as long as the pneumatic supply correctly provides compressed air, the clamping jaws are held under a prestressing force by precisely this pneumatic action at a distance from the piston rod.

As a result of the purely vertical lifting movement of the upper mould 54, the baking machine according to the invention is particularly suitable for manufacturing comparatively deep and correspondingly high-walled casings, cups or other moulded elements.